HYALURONAN-BASED HYDROGEL SCAFFOLDS - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 191

and lipophillic drugs, including nalbuphine, indomethacin, and the
nalbuphine prodrug, were used as model drugs in an in vitro drug
release experiment.
An HA-dextran hybrid hydrogel, among other HA-based hybrid
hydrogels, was also fabricated to evaluate either its cytotoxicity or
its drug delivery for its application as an injectable form for implan-
tation in ferret vocal fold, even though other numerous studies have
been done on dextran orHA only. 53 , 85

9.5.3 HA-Synthetic Polymer Hybrid Hydrogels
HA-syntheticpolymerhybridhydrogels werefabricated byemploy-
ing hydrophilic polymers such as PEO, PVA, Pluronic polymers,
and others. Among those polymers, PEO was adapted in many
experiments as a counterpart of HA, due to its excellent bio-
compatibility and well-known physicochemical characterizations in
biomedical applications. An HA-PEO hydrogel, using thiol function-
alization, was developed by Zheng Shu et al. for the design of HA-
PEO hydrogels for tissue engineering and drug delivery. 33 Thiolated
HA derivatives were chemically coupled to

α β

-unsaturated esters
and the amide of PEO. After induction of in situ HA-PEO hydrogel
by mixing HA-SH and PEO-diacrylates in several minutes, it was
applied as a scaffold for bone tissue engineering. 31 Low cytotoxicity
of human tracheal scar fibroblasts was observed in the HA-SH pre-
cursor solution. Also in vivo chondrogenesis of mesenchymal stem
cells in the HA-PEO photopolymerized hydrogel was studied with
addition of transforming growth factor (TGF)- β 3 in a nude mouse.
Mesenchymal stem cells in the HA-PEO hydrogels containing TGF-
β 3 produced higher-quality cartilage on the basis of expression of
cartilage-specific genes and production of proteoglycan and colla-
gen II. When used independently, TGF- β 3 and HA alone induced
cartilage-specific gene expression and collagen II production with
reduction of collagen I production, even though TGF- β 3 was essen-
tial for proteoglycan production. 86 HA-PEO hydrogels synthesized
by HA-ADH and methacrylated PEO were also applied to the regen-
eration of ischemic heart 84 and postoperative pericardial adhesion
prevention. 87

,